SELF-HEALING OF MORTAR CRACKS: THE ROLE OF HUMAN PATHOLOGICAL BACTERIA

الملخص

The characteristics of self-healing related to N-type cement mortars, the addition of human
pathological bacteria to enhance mortar durability, and compressive strength thus reducing
maintenance cost and manpower after crack initiation. Bacteria have been examined by using
two types of biological agents: Proteus mirabilis and E. Coli bacteria. Mortars are formed
from a combination of Portland cement and ordinary sand, treated by Proteus mirabilis and E.
Coli bacteria with different concentrations. The mechanical properties of the treated mortars
are measured and the mortars were characterized by means of Fourier-transform infrared
spectroscopy (FTIR), scanning electron microscopy (SEM), and electron energy dispersive
spectroscopy (EDX). This study shows that Proteus mirabilis and E. Coli assist the formation
of calcium carbonate inside the mortar micro-pores leading to enhancement of the
compressive strength and hardness of the mortar specimen. This emphasizes the possibility of
activating the self-healing characteristic of the cement mortar and its utilization for cracks
treatment and repair